MacGREGOR: AMOUNT AND PROPORTIONS OF DDT 



DDT 



< 



DDE ^-(little or no metabolism) 



DDD »-DDMU ►►(continued metabolism) 



Kelthane—»-Dichlorobenzophenone— ♦-(continued metabolism) 



Since we have no measurements of Kelthane, the 

 scope of this paper includes only the measurement 

 of the metabolism of DDT to DDE and DDD. As 

 mentioned earlier, the effluent from the Montrose 

 plant was already partly metabolized (Carry and 

 Redner, 1970). In seven samples taken between 14 

 August and 24 November 1970, the total DDT 

 portion of the effluent contained 74% (range 

 62-84) of DDT, 5% (3-7) of DDD, and 21% (9-35) of 

 DDE. During this period the effluent contained 2 

 lb or less of DDT per day. The proportions of DDT, 

 DDD, and DDE at the time when dumping was 

 650 lb (295 kg) per day were 73:2:25. 



At the beginning of this investigation some pes- 

 ticides were separated on other columns to con- 

 firm the identification of DDT and its metabolites. 

 Additional confirmation was obtained by dehy- 

 drochlorinating samples with alcoholic KOH 

 which converts DDT and DDD to their respective 

 ethylene derivatives, DDE and DDMU, but does 

 not change the PCB, Aroclor 1254. 



Because there are so many possible sources of 

 variance to the estimates of pesticide content, we 

 cannot obtain a precise measure of this error. 

 Based on the least accurate measurements made 

 in the course of analysis, the standard error of the 

 amount of pesticide in a sample should be about 

 plus or minus 10% . The error may be increased by 

 shortcomings in methodology and by the presence 

 of other peaks that interfere with those to be quan- 

 tified. At low pesticide values the error increases, 

 and it may be more like plus or minus 100% at 

 values on the order of 10 ppb. However, the abso- 

 lute error is only a few parts per billion also and 

 makes little difference when values that differ by 

 orders of magnitude are being compared. 



In the myctophid samples, Aroclor 1254 seemed 

 to be the only substance that contributed peaks on 

 the chromatogram of any significance which could 

 interfere with quantification of the DDT series. 

 Six Aroclor 1254 peaks span the retention time 

 range ofp,p'DDE, o,p'DDD, o,p'DDT, p,p'DDD, 

 andp,p'DDT (Figure 3). In all the marine sam- 

 ples examined, o,p 'DDT and o,p 'DDD are present 

 in either very small quantities or not detectable 

 at all unless the samples contain very large quan- 

 tities ofp,p'DDT orp.p'DDD. In the myctophid 

 samples, Aroclor 1254 seems to maintain its in- 



tegrity very well. There is no apparent selective 

 breakdown of its components, and the pattern of 

 peaks from myctophid samples containing this 

 PCB and very little pesticide closely resemble the 

 Aroclor 1254 standard (Figures 3 and 4). 



RETENTION TIME IN MINUTES 



Figure 3. — A. Aroclor 1254 standard; column: 1.5% 

 OV-17/1.95% QF-1, 100/120 mesh Supelcoport.B. Sample of two 

 Stenobrachius leucopsarus each 20 mm standard length (SL) taken 

 in July 195 1 . at CalCOFI station 70. 100. About 0.54 ppm Aroclor 

 1254 with peak no. 5 increased slightly by 0.2 ppm DDE and peak 

 no. 10 by 0.3 ppm DDT. Less highly chlorinated Aroclor peaks no. 

 1, 2, and 3 may be breaking down in the environment; more highly 

 chlorinated peaks (no. 4 through 10) tend to maintain their integrity 

 of pattern. Same column as A. C. Standard of six DDT analogs. 

 Same column as A. D. Sample of a 33-mmS. leucopsarus taken in 

 November 1955 at CalCOFI station 83.40. This sample contains 

 2.3 ppm total DDT. Because of the high DDT content of this 

 sample, it was not concentrated as much as sample B. It probably 

 contains at least half as much Aroclor 1254 as sample B. Same 

 column as sample A. 



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